In　order　to　solve　the　problem　that　the　high　computational　burden　of　the　multiple　signal　classification　algorithm　of　non-circular　signal　(NC-MUSIC)　in　direction-of-arrival　(DOA)　estimation,　a　novel　computationally　efficient　DOA　estimation　algorithm　based　on　subspace　rotation　technique　was　proposed.　Firstly,　the　partitioning　of　noise　subspace　matrix　and　the　subspace　rotation　technique　(SRT)　were　used　to　construct　a　new　reduced-dimension　noise　subspace.　Then,　the　two-dimensional　peak　searching　was　converted　to　the　one-dimensional　peak　searching　on　the　basis　of　the　separation　of　variables　and　the　orthogonality　between　the　new　reduced-dimension　noise　subspace　and　the　space　spanned　by　the　columns　of　the　extended　manifold　matrix.　The　proposed　algorithm　can　enhance　the　computational　efficiency　by　means　of　the　conversion　of　the　two-dimensional　peak　searching　into　the　one-dimensional　peak　searching　and　the　removal　of　redundant　computations.　Theoretical　analysis　and　simulation　results　show　that　the　proposed　algorithm　can　reduce　the　computational　complexity　to　less　than　5%　as　compared　to　NC-MUSIC　algorithm　on　the　premise　of　ensuring　the　accuracy　of　DOA　estimation.　Especially,　the　efficiency　advantage　of　the　proposed　algorithm　is　more　obvious　in　scenarios　where　the　large　numbers　of　sensors　are　required.　©　2020,　Editorial　Board　of　Journal　on　Communications.　All　right　reserved.